cathodic protection rectifiers

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. 23478 -VOO-EYIO-OOO02-OI I m No. BechtelCmofation 23A71t I I SUPPLIERDOCUMENTREVIEWSTATUS I I STATUS NO. I 1 WJdcmayplumcd 2 a RewsoandmsuhIL WofkmYkm=d wbPC4bmWalIOM 0fdunge4mdrabd 3 .Rememdmsutmt MINYmtPIuc-4 4Jq R@w.#notqned Watimypruyad.

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Cathodic Protection Rectifiers

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Page 1: Cathodic Protection Rectifiers

. 23478 -VOO-EYIO-OOO02-OI

ImNo.

BechtelCmofation 23A71t I

I SUPPLIERDOCUMENTREVIEWSTATUS I

I STATUSNO. I1 ❑ WJdcmayplumcd

2 a RewsoandmsuhIL WofkmYkm=d wbPC4bmWalIOM 0fdunge4mdrabd

3 ❑.Rememdmsutmt MINYmtPIuc-4

4Jq R@w.#notqned Watimypruyad.

Page 2: Cathodic Protection Rectifiers

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Page 3: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

A. INTRODUCTION

This Operation Manual has been prepared for the specific rectifier as identified by

the serial number on the unit. It is recommended that it be kept inside the Rectifier case

for quick reference. Store it in the space provided. Do not place it so that it will impede

air flow through the case.

RTS Cathodic Protection Rectifiers are built by skilled personnel and are designed by

an engineering staff with years of experience in the field. Every effort has been made to

use the latest in reliable components, so that these rectifiers are of the highest quality

consistent with reasonable costs.

RTS maintains a file on every rectifier by serial number only, Therefore the SERIAL

NUMBER should be specified when requesting information on or ordering parts for this

rectifier,

B. DELlVERY INSPECTION

If damage has occurred in shipment, FILE A CLAIM WITH THE CARRIER

IMMEDIATELY. If it is necessary to contact your supplier or the manufacturer concerning

damaged or missing components, be sure to include ALL information such as Serial

Number, Purchase Order Number and Invoice Number. This will ensure that you obtain

proper and expeditious service.

C. INSTALLATION

Proper rectifier installation procedures are necessary to ensure the integrity of the

cathodic protection system. These procedures are as follows:

1. Check all electrical connections to make-sure they are tight. It is a good idea

to re-tighten all bolts, especially those which carry electrical current.

2. Select the mounting site for the rectifier; paying special attention to

accessibility, proper ventilation, shielding from sources of high ambient

temperatures, and most importantly, convenience to A.C. and cathodic

protection connections.

3. Mount rectifier securely on mounting pad, wall or post.

4. Have a qualified electrician make electrical connections, following the

electrical and local codes. A disconnect switch is required ahead of the A.C.

input to the rectifier.

1

Page 4: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

5. BEFORE ENERGIZING, double check to ensure the rectifier is sized to take the

A.C. input being applied.

6. ENSURE CORRECT POLARITY ON D.C. CONNECTIONS, connecting negative

to the structure being protected and positive to the anode leads.

7. BEFORE turning on the input breaker, ensure the taps are at their lowest

setting: COARSE ‘A’, FINE ‘7‘. Tap adjustments should always be made from

the lowest setting to prevent damage to the rectifier or prematurely blowing

the output fuse.

8. Initially set the rectifier to approximately half of the desired output by movingthe tap bars as required. The COARSE adjustment bar should be moved one

step higher; turn unit on and check output and repeat as required until output

is close to desired output. Then the FINE adjustment bar can be similarly

moved to bring output to desired level. If everything appears normal, allow

the unit to run for several minutes to allow for examination, then proceed to

set the Rectifier to your desired output.

9. The Rectifier should be operated at the required D.C, output current for about

one hour to determine that there are no defects in the connections. Shut the

A.C. power OFF at the disconnect switch and immediately feel all current

carrying connections to see that none of them are overheating. Connections

may be warm, but should not feel hot.

10. Air cooled rectifiers utilize natural air convection for cooling, and are typically

manufactured with screened openings top and bottom. Make sure these

vents are never obstructed by plugged screens or by laying the rectifier

manual on the bottom.

11, Periodically monitor the rectifier, re-adjusting as necessary to maintain the

level of cathodic protection current required.

D. MAINTENANCE

C.P, rectifiers have no moving parts (other that the meters),

maintenance is largely of a preventative nature. Bear in mind there are

conditions which will affect the life of a C.P. rectifier:

1. Excessive component temperatures.

2. Voltage surges and lightning.

3. Excessive current output.

and therefore

primarily three

Page 5: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

Meter readings should be checked against an accurate meter. A quick calibration for

ammeter accuracy can be made by measuring the millivolt drop across the shunt with a

high input resistance meter such as an electronic voltmeter set to the millivolt scale. The

actual reading is given by:

I(d.c, ) = E x I(shunt)

50

Where: I(d.c.) = Actual D.C. output in amperes

E = Millivolt reading across shunt

I(shunt) = Shunt size(corresponds to the full scale deflection of ammeter)

Meter accuracy should be within 2% of full scale deflection, combined with an

allowance for temperature of 0.85% per 10 degrees C. for temperature other that 25

degrees C.

A periodic check of rectifier conversion efficiency will also indicate if the rectifier is

functioning properly. If an A.C. wattmeter is unavailable, use the pole mounted watt-hour

meter. This, of course, is if no other electrical loads are drawing power when the A.C.

draw is being determined.

A.C. Power (in watts) = 3600 KN

Where: K =

N=T=

T

Watt-hour meter constant (on meter face)

Number of revolutions of watt-hour meter diskTime in seconds for the number of revolutions

(minimum of 60 seconds for best accuracy)

D.C. Power is the product of VOLTS D.C. x AMPERES D.C.

Rectifier conversion efficiency will be:

D.C. Power Out x 100 = % conversion efficiency

A.C. Power In

For tap-adjusting silicon diode rectifiers, conversion efficiencies of approximately

75’?Aofor single phase will indicate a properly functioning rectifier.

Page 6: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

Maintenance can be the best deterrent against rectifier failure due to excessive

temperatures. Regular checks for blocked venting or heat from a man-made source should

be undertaken. Periodic re-tightening of electrical connections is good insurance against

future trouble,

CAUTION: Hazardous voltages are present within the rectifier.the A.C. power at the nearby disconnect. The rectifier A.C. breakerremove all incoming A. C. power from the rectifier.

ALWAYS interrupt

DOES NOT totally

A temperature probe is a very useful preventative maintenance tool. The following

is a guide for maximum temperatures. These temperatures are based on a 45 degree C.

ambient, The difference between 45 degrees C. and the ambient temperature at time of

testing should be subtracted from the readings in this table:

COMPONENT TEMPERATURE TABLE

COMPONENT MEASUREMENT POINT MAX TEMPERATURE

Moulded Bridge moulded body 110 degrees C,

Silicon Diode mounting stud 115 degrees C.

Transformer primary winding 160 degrees C.

Filter Choke winding 160 degrees C.

Filter Capacitor case 80 degrees C.

Output Fuse metal ends caps 130 degrees C,

Current Shunt resistive element 75 degrees C,

Electrical Corm. bolt or screw 90 degrees C.

Electrical Wiring wiring harness 90 degrees C,

Maintenance against voltage surges is largely one of ensuring the lightning

protection supplied with the unit is intact. . Keep - motor and similar surge

electrical equipment from being attached to the same A.C. power lines wherever

Lightning rods may prove valuable in high lightning strike areas.

and surge

producing

possible.

Maintenance against excessive current output requires monitoring of rectifier

outputs, and logging data so as to predict when an over current situation may arise. If a

protective device (input breaker or output fuse) has operated, it is an indication of overload

or component failure. Always replace fuses with the same rating and type. Check the

rectifier diode bridge before re-energizing to ensure all diodes are operative,

3

Page 7: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

E. TROUBLE SHOOTING

Although quality construction and preventative maintenance will reduce rectifier

down time, failures will occasionally happen. A good knowledge of rectifier operation will

enable a potential problem to be quickly traced and repaired.

RECTIFIER TEST EQUIPMENT:

The following equipment is essential for basic rectifier trouble-shooting.

1. Electronic multimeter, preferably one which can measure up to 750 VAC and

that has a diode check range. ( Fluke 75 or 25)

2. Clamp-on A.C. ammeter, Fluke 801-600 or Amprobe ACD-I

3. Temperature probe, Fluke 80T-I 50 degrees C.; range of 50° to + 150° C.

4, Dummy resistive load, 2-5 ohms, 1000 watt capacity..

5. Hand tools. 1/4” - 3/4” S.A. E. combination wrenches; 1/4” - 1/2” S.A. E.

nutdrivers; 3/1 6“, 1/4” and 5/16“ blade screwdrivers; #l, #2 and #2 long

socket screwdrivers; 3/8” drive S.A. E. socket set with deep sockets.

6, Small set of clip-leads.

TROUBLE SHOOTING PROCEDURE:

The majority of rectifier faults are easy to diagnose. They include loss of A.C. input,

blown fuses, loose terminals, faulty meters, blown M.O.V. suppressors, open circuits,

faulty cathodic load connections, and lightning damage. Visual inspection and smell can be

very useful for the initial examination of a faulty rectifier for the above faults.

The initial inspection should be followed by a systematic isolation of various rectifier

components to determine the cause of non-operation. This should be conducted as

follows ( refer to the schematic for test point locations).

CAUTION: Beware of hazardous electrical voltages and where they are present in

‘the rectifier. [f doing any work on a rectifier other than taking voltage or current

measurements, DISCONNECT THE A.C. POWER, preferably at the rectifier disconnect, not

just using the rectifier circuit breaker.

Page 8: Cathodic Protection Rectifiers

1.

2.

3.

4.

5.

6.

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

Check whether A.C, voltage is present at the rectifier input terminals and that

it is the correct level for the rectifier input rating. Provided the input breaker

has not tripped OFF, this voltage check should be done with the rectifier ON.

This will eliminate any static voltage reading such as might be experienced if

only one A.C. line entering the rectifier is broken.

If the input breaker continues to trip OFF when energized, this usually

indicates a short circuit within the rectifier. Proceed as follows;

a)

b)

c)

d)

An

Remove both tap bars (shown by Coarse & Fine taps on schematic) to

isolate the bridge, Again energize the breaker. If the breaker now

holds, the problem is a shorted diode(s) in the stack. Check stack and

replace defective diode(s). (See #7 below)

With the rectifier disconnected from the A.C. supply, do an ohmmeter

check between ground lug and the load side(s) of the input breaker

(right side of CB1 on schematic). Any detectable resistance willindicate a primary to ground breakdown. A ‘Megger’ test instrument is

preferred for this test if available. Any fault will necessitate

replacement of the transformer.

Visually inspect the transformer for any signs of burned or shorted

windings.

Check for shorted A.C. lightning arrestors.

intermittent voltage reading nearly always indicates a loose or burned

connection.

Verify there is transformer secondary voltage. A measurement of the voltage

across COARSE ‘E’ to FINE ‘5’ should be 1.35 to 1.6 times the D.C. output

voltage rating of the rectifier,

Verify the COARSE steps as being approximately 20% of the measurement

(item 4 above) and that the FINE steps are approximately 20% of the voltage

of each COARSE step.

Measure the A.C. voltage at the diode stack (same as connection points of

MOVI on schematic). It should be the same as measured across the tap

bars, otherwise the fuse has operated or the wire is burned or broken,

6

Page 9: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

7. Conduct a diode check of the stack as follows:

a) Disconnect power from the rectifier and remove the tap bars.

b) With the multimeter set on the diode check range, place the POSITIVE(Red) lead on the stack negative terminal (negative side of shunt on the

schematic) and touch the NEGATIVE (Black) lead to the stack A.C.

terminals (same as connection points of MOVI on schematic). A good

diode will measure 250 to 1000 ohms and the Fluke meter will give a

single BEEP. This will check diodes D3 and D4. An open or short

circuit reading will indicate a faulty diode.

c) Similarly, place the NEGATIVE meter lead on the stack positive terminal

(connection point between DI & D2 on schematic) and now touch theother lead to the stack A.C. terminals. This will check diodes D1 and

D2.

d) Replace faulty diodes with the same type and polarity. Do not over-

tighten stud mount diodes. Recommended torques are:.

1/4” Stud Type 30 inch-pounds

8, Check for the presence of voltage at the D.C. positive and negative terminals

of the stack and at the rectifier D.C. output lugs. If the voltage is present atthe stack but not at the terminals, check for open circuits in the wiring (or a

blown D.C. fuse).

NOTE: With no load, a sensitive electronic meter may read a static

potential which is much higher that the actual D.C. voltage. It

may be necessary to place a small test load across the rectifier

output lugs which will eliminate the false reading of the

electronic voltmeter,

9, If the correct D.C. voltage is present at the rectifier output terminals but no

current flows, there is an open circuit in the cables leading to the C.P. load.

10. Verify {ectifier meter readings are correct with an electronic meter. Rectifier

meters may indicate a rectifier fault when no actual fault exists.

7

Page 10: Cathodic Protection Rectifiers

RTS MANUFACTURING DIVISIONCATHODIC PROTECTION RECTIFIER

OPERATION MANUAL

11. Meter switches are often a source of meter reading faults, especially in

corrosive or H2S environments. If these are on-going problems,

environmentally sealed switches should be used to replace normal types.

Their added cost may save future repair work and down time. Jumpers

carefully placed across the closed contacts of a suspect switch will isolate

any high resistance contacts.

12. Lightning and surge suppressors can be checked for shorts by isolating them

from the circuit and checking with an ohmmeter. Normally these shouldexhibit an open circuit (infinite resistance).

F. SAFETY

Cathodic protection rectifiers do present

unfamiliar with the workings of a unit. Electrical

few guidelines:

electrical shock hazards to personnelsafety can be enhanced by following a

1.

2.

3.

4.

5.

6.

7.

8.

When approaching a rectifier to inspect or repair, always remember to touch

the case latch with the BACK of your hand first. If you feel any voltage “‘Tingle’ DO NOT grab the lock or latch with your hand as you may not be ableto let go, You should turn off the A.C. power at the external disconnect and

call an electrician.

Understand where potential hazards exist so as not to contact them bodily or

with tools.

Work in pairs when working on energized equipment.

Use a rubber mat to stand on.

When taking readings use only one hand if possible.

Lock out a supply disconnect or circuit breaker to prevent accidental re-

energizing of the circuit.

Wear safety glasses when soldering any connection.

When in doubt on a particular test procedure, contact an experienced

technician or the factory.

8

Page 11: Cathodic Protection Rectifiers

I

CORRPRO CANADA, INC. RTS MFG. DIV. RECTIFIER SPECIFICATION SHEET

CUSTOMER: HARCO TECH., MEDINA P.O.: 34704 DATE: DECEMBER 01, 1997

MODEL NO: CSAYSE 60-12 SERIAL NO.: C-972092 W.o.: 13339-1

A.C. VOLTS: 115/230 D.C. VOLTS: 60 PH.: 1 CYCLES: 60 INPUT V. A.: 1095A.C. AMPS.: 9.5/4.75 D.C. AMPS : 12 O/P CKTS: SINGLE TYPE: TAP-ADJUSTED

QTY. ITEM PART NUMBER DESCRIPTION

1 ENCLOSURE A-1 STANDARD, CT&D 14 GAUGE MILL GALV. STEEL, WHITE

1 CHASSIS A-1 STANDARD 14 GAUGE MILL GALV. STEEL, WHITE

1-PR PHENOLIC MTG. BKT. A-1 STANDARD 14 GAUGE MILL GALV. STEEL, WHITE

1 FRONT PANEL A-1 STANDARD, RTS NEMA “XX”, 3/16” X 9.75 X 14.00

I TRANSFORMER T-601 2-E RTS, 5-COARSE, 5-FINE TAPS

VOLTMETER 0-75 VOLTS F. S. D., / 60 RED LINE

1 260-300-E50 YOKOGAWA

AMMETER 0-15 AMPERES F. S. D./ 12 RED LINE

1 DIODE BRIDGE 35 MB60A INTL. RECTIFIER, 35 AMPERE, 600 VOLTS PIV.

1 HEATSINK #1024 X 3.5’’/EQUlV. WAKEFIELD, ALUMINUM, BLACK ANODIZED

1/1 AC BREAKER JAI-SD3ABOI DAW-1015.O HEINEMANN, 10/5,0 AMP. 230VAC, 2-POLE

1 SHUNT 15 AMPERE, 50 MV. HOLLOWAY TYPE “SW”

1 A.C. ARRESTOR SIOV-S20K250 SIEMENS, 130 VOLTS, 130 JOULE

1 D.C. ARRESTOR SIOV-S20K130 SIEMENS, 130 VOLTS, 68 JOULE

1 SECONDARY SURGE SIOV-S20KI 30 SIEMENS, 130 VOLTS, 68 JOULE

2 FUSE CLIPS C-10, ILSCO PLATED, FOR 9/1 6“ DIA. X 2“ FUSES

1 FUSE NON-1 5/Equivalent EDISON, 15-AMPERE 250 VOLTS AC

RHEOSTAT RHI 50-1.0 MEMCOR, 1.0 OHM, 150 WATT

RHEOSTAT KNOB 2514-010-017 MEMCOR

DIALPLATE 2491-020-001 MEMCOR

RHEOSTAT PLATE A-1 STANDARD, C. T.&D. 1/8” ALUMINUM

SWITCH S-335 /EQUIV. NKK DPDT, “SWITCH #2 - VOLTS”

1 SWITCH S-338 /EQUIV. NKK DPDT, “AMPERES - VOLTS”

1 TERMINAL BLOCK 10-142, JONES 30 AMPERE, 300 VAC, “COARSE-FINE TAPS”

1 TERM. BLOCK BKT. 66-X-0050 FOR El-225 & EI-300 LAMINATION

1 AC TERMINAL 8-142, JONES 30 AMPERE, 300 VAC, C/VV BARRIER

2 DC LUGS XT #4 - #14, ILSCO PLATED, (1) POSITIVE (1) NEGATIVE

II uNOTES:

1. RECTIFIER EQUIPPED WITH SINGLE OUTPUT CIRCUIT.

.

AC WIRE SIZE: # 14 TEW SEC./DC WIRE SIZE: # 14 TEW

Page 12: Cathodic Protection Rectifiers

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2 .) FOR ? t5 VAC lNPUV. JUMPER 1-2 c 3-4FOR 230 VAC INPUF J.IMpER 2-3 ONLy.

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